HDG, Pickling, Polishing, Coating & Anodized Surface Treatment Process Introduction

Hot dip galvanizing is a form of galvanizing in which a surface treated metal is immersed in a bath of molten zinc at a temperature of about 450 °C (842 °F). The zinc forms a layer of compounds on the metal surface, a process that helps to protect the metal from corrosion. The hot-dip galvanizing process is divided into three basic steps: surface treatment, galvanizing, and inspection. Compared with other galvanized steel, hot dip galvanizing process is relatively cheap, the product is corrosion resistant, so it is widely used in agriculture, industry, automobile, construction, solar energy and other wet or corrosive environment. For example, our strut plank grating is galvanized in this way.

Strictly refer to international standard ISO 1461:1999, American Society for Testing Materials ASTM A123/A123M and domestic standard GB/T 13912-2002 testing requirements.

Advantages:

• Low cost
• Thick zinc coating
• Strong corrosion resistance
• The service life can be greatly improved by galvanizing process
• Coating adhesion is good, after plating, it can also undergo properly welding, coating and other processing

Disadvantages:

• The working environment is poor and polluted.
• The galvanized coating is thick but uneven.

It is an electrochemical finishing process, which takes the polished workpiece as the anode and the insoluble metal as the cathode. The two poles are immersed in the electrolytic cell at the same time, the selective anodic dissolution is generated through direct current ionization reaction, so as to achieve the effect of removing fine burs and increasing the brightness of the workpiece surface. The process leaves a shiny, smooth, ultra-clean surface finish. Wedge wire screens after electrolytic polishing, the surface of the products is bright and beautiful.

We strictly comply with ASTM B912 and YB/T 4377-2014 testing requirements.

Advantages:

• Consistent color and lasting luster.
• High production efficiency, low cost, can be mass processing.
• Enhance the corrosion resistance of workpiece surface, suitable for all stainless steel materials.

Disadvantages:

• There are many parameters affecting electrolytic polishing, so it is difficult to find the correct parameters.
• It is difficult to obtain good results for samples such as cast iron and inclusions.
• Electrolyte composition is complex, need to pay attention to safety operation when using.

Polyvinyl difluoride (PVDF) coatings are sprayed in a spray room through a liquid spray gun and are one of the most commonly used commercial and industrial coatings on the market. PVDF is a fluoropolymers resin that is highly inert and stable and has excellent resistance to weathering caused by sunlight, moisture or temperature. Our decorative perforated plates often use this process.

We strictly test product quality according to HG/T 3793-2019 standard.

Advantages:

• PVDF coating is resistant to UV radiation, has excellent color retention and will not fade with time.
• The coating has good adhesion, abrasion resistance and long service life.
• The coating is resistant to most chemicals and solvents, acids and corrosion.
• In addition to being able to self-extinguish, the PVDF coated material also produces little smoke in the event of a fire.

Disadvantages:

• Only matte finishes are available, while powder coatings can come in a variety of colors and finishes.
• More expensive than powder coatings.